The present invention relates to a color display control method and apparatus, for example, for a color liquid crystal panel employing a bit map display system.
For displaying a picture, graphic form, or character on a color liquid crystal panel with regularly arranged red, green and blue dots (i.e. picture elements) through use of a bit map memory assigned addresses corresponding to the dots of the color liquid crystal panel, it is customary in the prior art to employ the following method in the case of providing the display without gradation. When data is written into the bit map memory, the color of the dot of the color liquid crystal panel corresponding to each address of the bit map memory is checked under control of software, and 1 or 0 is written, as the above-mentioned data, into the corresponding address of the bit map memory, depending on whether or not the color of the dot corresponds to the color to be displayed on the color liquid crystal panel (a red dot if the color to be displayed is red and a green or blue dot if the color to be displayed is cyan, for example). The data thus written into the addresses of the bit map memory are read out therefrom in an order corresponding to that in which the dots of the color liquid crystal panel are arranged, and the dots are controlled by the read-out data in that order so that each dot is turned ON (lighted) or OFF (held dark) depending on whether the data corresponding thereto is 1 or 0.
The operation for providing a display with gradation is basically the same as mentioned above. When data is written into the bit map memory, the color of the dot of the color liquid crystal panel corresponding to each address of the bit map memory is checked under control of software, and data of plural bits, which indicates the brightness level of the color of the dot, is written into the corresponding address of the bit map memory. The data thus written into the addresses of the bit map memory are read out therefrom in the order corresponding to the order of arrangement of the dots of the color liquid crystal panel, and the dots are each turned ON, in that order, to the brightness based on the corresponding data.
With the conventional color display control method, however, it is necessary to check under control of software the color of the dot of the color liquid crystal panel corresponding to each address of the bit map memory when data is written thereinto as described above. This inevitably necessitates the use of complicated software and retards the processing for color display control.